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Wed, 02 Sep 2026 00:04:16 -0700 (PDT) From: Daehyeon Ko <4ncienth@gmail.com> To: Amir Goldstein Cc: Jan Kara , Miklos Szeredi , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] fanotify: destroy/add race leaves a mark on a detached connector Date: Wed, 2 Sep 2026 16:03:58 +0900 Message-ID: <20260902070359.4163607-1-4ncienth@gmail.com> In-Reply-To: References: <20260827045007.3831259-1-4ncienth@gmail.com> <20260828042421.964822-1-4ncienth@gmail.com> <63aj7jbfaoamdmcurlge2c2kqpliaifgq4vbythrrxpfyr5vtm@z64myom426zd> <67hq7zqnvp6onwwjp24axucgxbzsko2dphielupdfzmfyk6x57@bdeef7fjkqfa> <6n6r5zvcu5ojihyb52rhejlky7xrn2a2p4l2cgfut5lsscunek@bcnpy7bifjrs> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Amir, I tested the exact attached patch (SHA-256 9fa187507909ae14c8de8a117e775122e3daa425c69081b7115b3dc979fca14d) on Linux v7.2, commit 8d3ae59288f1, with an x86_64 KASAN kernel. The capless prerequisite probe passed as UID/GID 65534 with CapEff=0 and NoNewPrivs=1. I then ran the original reproducer command fanotify_destroy_add_race 10000 1 1024 256 in three fresh 2-vCPU boots. All three runs completed 10,000 iterations with 10,000 successful adds, zero add errors, and 10,000 fdinfo reads. The complete serial logs contain no fsnotify_conn_mask() warning, other kernel warning, KASAN report, Oops, panic, or kernel BUG, and both guest and host exited 0. This tests the originally reported race reproducer. I did not yet test the new permission/pre-content, duplicate FAN_DELETE_SELF, open_by_handle_at(), or NFS/export-filesystem semantics discussed later in the thread. Tested-by: Daehyeon Ko <4ncienth@gmail.com> Thanks, Daehyeon